shell script 引数と標準入力両方受け付けられる関数を作る

function infolog() {
  local prefix_text="[INFO]"
  local input=$@

  # Check if input is from a pipe
  if [[ -p /dev/stdin ]]; then
    while IFS= read -r line; do
      echo -e "${prefix_text} ${line}"
    done
  else
    echo -e "${prefix_text} ${input}"
  fi
}

$ ls | infolog
[INFO] file1
[INFO] file2
[INFO] file3
 
$ infolog Hello, world!
[INFO] Hello, world!